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Friday, December 26, 2008

Guestpost: Christoph Schiller about Motion Mountain

"Please present the free Motion Mountain Physics Text and yourself!" Sabine wrote me some time ago. I answered that I first wanted to put the new version online. That is now done; it can be downloaded at www.motionmountain.net.

For a long time I carried the dream to tell the story of physics in the way I would have liked to hear it as a student. Simple, vivid, up to date - and stimulating. I wanted to write a text that is never boring, always challenging and surprising. Even though, of course, physics states that there are no surprises in nature.

My own physics studies, in the late seventies and early eighties in Stuttgart, had left me with three main impressions. (1) Physics is very interesting. (2) Most physics books are awful, in all languages. (3) Physics teaching is often even worse than its books - and often much better. My PhD time in France and Belgium confirmed the impressions. I wanted to change at least the book part.

I started writing in 1990, and now, in 2009, with 1600 pages, 600 photos, films and illustrations, 1700 challenges and puzzles, 900 internet links, the result is slowly realizing the original vision. The subtitle "The Adventure of Physics" expresses the tone in which the text presents the topic. Now in its 22nd edition, the text is a pdf file for free download. To get an impression, here are the topics that are newin this edition:

The new edition now explains how it is possible to plunge a bare hand into molten lead, includes a film of an oscillating quartz inside a watch, explains how it is possible to type a letter by controlling a computer with thought alone, includes a film of a solar flare, explains the fifteen ways that colours appear in rocks plants and animals, explains the connection between cats and gauge theory, adds more ways in which the human eye invents colours that are not there, includes a list of laser types and applications, includes many images of crystals, explains how physics Plotinus and christianity come together to show that the universe and god are one and the same, adds the handcuff puzzle and several other puzzles, explains how jet pilots frighten civilians with sonic superbooms produced by fighter planes, presents the most beautiful and precise sundial available today, adds a simple photographic proof that the Earth is larger than the Moon, improves the presentation of elementary particle physics, adds a photo of a red rainbow, gives the latest discoveries on the Galileo trial, presents a fascinating mathematical aspect of Ohm's law, states the hardest open math problem that you can explain to your grandmother, and much more.

The full text presents mechanics, electricity, thermodynamics, special and general relativity, quantum theory, and a bit of unification, all explored in a way that should be in the reach of an undergraduate. The structure of physics and the adventures one encounters are shown in a graphic that describes the exploration:The idea of the text has always been to mix theory and experiment, in contrast to many courses at university. I wanted to add topics that appeal to young men and women (including sport, biological matters, medical matters, music, sex, games, machines). The idea was also to stimulate those readers that are more intellectual and those which are more practically inclined - and it should be fun and challenging to read for somebody from outside physics, for a student, and for a physics professor alike. The text now contains many self-contained stories, but also follows a narrative thread.

I always wanted to write a complement for all those texts that are write-ups of lecture notes: fewer formulae, more stories, more ideas. This probably is a result of my own experience as young boy and young man living in many countries in Europe and Asia.

There is a now a French translation of the first 560 pages (more are coming), a Spanish translation of 80 pages, with more coming, and also an Italian and a German version in the making. There is also a charitable non-profit association that finances all this, sponsored by a few donors, the largest being the Klaus Tschira Foundation. But as usual, funding is never sufficient...

The funds are used for computers, software, editors, designers, internet presence. So far, no money has been used for the writing or the content itself. And it was decided not to generate any income, neither with ads nor with other means. Job and family are limiting the total effort, of course.

The newest project is a version for the blind, which we hope to present as a first prototype in the summer. This was triggered by John Gardner from Viewplus, a blind entrepreneur and physicist.

A rewarding aspect has been that more and more professionals are providing images, references, and also corrections. I have many email exchanges with researchers and teachers all over the world who are helping to improve, correct and complete the text. For example, the sections on astronomy, on optics, on the climate, on relativity, on knots, on material science, and on animals and plants have gained much in this way. If you have a comment or suggestion, let me know. I'll do my best to implement it in the next edition. In total, over 200 people have provided suggestions and material, and the book would not be what it is without them. They are all listed in the acknowledgements.

Several young readers have told me that they decided to study physics partly because they were inspired by this text. Therefore I hope to be able to continue the project for a few more years. There is still much to be added - my present "to do" list has 1060 open items. In the meantime, there is only one thing to say:

7 comments:

Interesting attempt, Christoph, congratulations on the huge work being done! Physics with a human face, so to say, but without losing rigour. Good idea that may be limited only by fundamental limits on any physics account: further knowledge development. In that respect today's moment may be not the most favourable one (physics rather in crisis), but then the expected development itself may depend on suitable, non-standard presentation of the present level. It's good also to have it freely accessible on the web.

Having had a look at your book, I have a particular question. The main idea of the work (which seems good to me) is motion, in all its guises and aspects, as the main subject of physics. However, in the beginning chapter you state (p. 22):

“Motion is mysterious. Though found everywhere – in the stars, in the tides, in our eyelids – neither the ancient thinkers nor myriads of others in the 25 centuries since then have been able to shed light on the central mystery: what is motion? We shall discover that the standard reply, ‘motion is the change of place in time’, is inadequate. Just recently an answer has finally been found. This is the story of the way to find it.”

It sounds as “after 25 centuries of obviously vain searches, the sacred answer to the main question has finally been found and ...”, and this answer is assumed then to be found in the book totally devoted to the search details and particular results. If it's not just an interest-provoking “appetizer”, what's the recently found “right” answer you refer to and where can it be found (in the book or elsewhere), according to you? The diagram on page 15 you reproduce in this post seems to imply that the answer is the “(Unified) theory of motion” that somehow summarises all the rest, but still what is the simple answer to that simple “main question” that “has finally been found”? Fun is good, but keeping promises either is...

It is truly amazing and wonderfull that you would have been inspired to write such a book, let alone make it available for free. Being a lifelong science enthusiast myself, with physics my primary interest, I can assure you I need little encouragement. That said I would both agree and admit that from personal experience it is hard to find well written material that lends the reader both accuracy and at the same time aids to instill that sense of wonder that I feel so necessary for someone to become truly interested as to continue to be enriched by the learning.

I have downloaded your book and as time permits am looking forward to reading it. I have also downloaded it onto a USB memory stick I carry with me, so that wherever I might go where there’s a computer available I might have chance to continue. In viewing your web site I noticed for a variety of reason, not the least being that you still don’t consider your work completely finished, it’s not available in a paper version. Don’t take this wrong as I both realize and appreciate that pdf makes things much more widely available and accessible.

Likewise I’m reminded of what my father often said, that one should never stand in a bread line and ask for toast. The only reason I ask, which in part may relate to my age and generation, is that I still find that the paper format I can read more comfortably and for extended periods. What I can tell you is that if it is or ever becomes so available such a book would be for me worth any reasonable price.

So thank you again for what I consider a wonderful Christmas present and may I extend my thanks all those that have contributed in either work or funding.

Well ... This e-book is lengthy, comprehensive, well-written enough, and free - so I only have "little" to complain about. But that critique is over a big-deal issue, namely the measurement problem in quantum mechanics. Christoph, you present the standard argument from decoherence on why we don't observe macroscopic superpositions, how can the wave function "collapse" etc. But that standard argument is based on circular reasoning and a fallacy of introducing at the outset, the very thing it seems that you are explaining. You reference the density matrix. The DM includes a classical-type probability (in effect) of what kind of WF is present. It also includes, at the outset, "probabilities" based on squared moduli of those WFs. Decoherence advocates claim to explain how or that probabilities emerge from the coexistence of these WFs and how external influences change and entangle their phase relations, without some intrusion of a collapse "mechanism" into the deterministic (in principle) evolution of these WFs. But if that is so, then it was wrong to just stick that portion of probability deriving from squared moduli into the DM "to start with." Those probabilities are supposedly what you are trying to explain from superposed states in evolution, you can't just take the desired outcome and stick it into the alleged mechanism first - that would be a classic "circular argument." So it is neither surprise nor accomplishment, when a circular argument ("cheating" in the logic: unintentional of course and a common temptation, but still fallacious) seems to derive exclusionary probabilities instead of coexisting states (like "alive and "dead" cat) - because you already put them there at the start! That's no valid way to "explain" how or why something happens.

Instead, the only legitimate way to try and derive "observed results" from WFs would be a DM that combined the probability mix of different WFs and the amplitudes themselves, kept as amplitudes, and see what happens. If we do it this way, now without the circular fallacy, we continue to have all the original "states" that were waved off by slight-of-hand by the decoherence argument, regardless of changes in phase relationships. These other results are again not surprising: the goal of statistical outcomes was not surreptitiously introduced in the back door, and could not emerge, given a non-fallacious sequence of thought. Hence decoherence does not - pace the attempts of those I call decollusionists with a wink - allow for statistics to emerge naturally from having different “states” interact with an environment and/or each other. It doesn’t anymore than the very presence of decohered classical waves would lead to a “statistics” or elimination of one or more components. How could it?

“The states don’t interfere anymore” is stated as if the state-selecting (ie, “collapse inducing”) consequences of that were self-evident. They aren’t. Interference only produces a pattern of “hits” instead of intensity distributions anyway, if there’s something additional and intrusive to the “wave nature” to localize effects of the waves/states that act like waves at the outset. (Again, the need to avoid circular argument.) Even the concept “interference” is misleading because it refers to assessment and appreciation of a built-up global pattern. Superposition is more fundamental and always happens anyway on an individual basis. Amplitudes always add up accordingly via superposition, regardless of whether we then have a pretty “interference” pattern or not. So we are still left with why does one detector click and not the other when the photon WF goes to both of them (it does go to both, right?), by extension the original "cat" problem, etc.

To summarize and conclude and as I’ve said elsewhere: if a multitude of "states" were presumed to exist before "decoherence" began randomizing their phases, that in itself wouldn't "get rid of" some and not others. They would just be superposed states with messy phases, all of them still effectively "there" however. It would just be a messier combination of the possible outcomes. Hey, remember that things like x and y polarization waves don't interfere anyway, they are still both present etc. together without one in effect winning over the other.

I can't explain the supposed experimental verification of "decoherence time" except that it is possible to misinterpret the logical consequences of outcomes. Also, in no case can a fallacious argument be allowed to stand – no matter how appealing or even how “useful” it is. Something must change. And I do have a possible counter-result: random decay of structureless particles, in free space. Take a muon moving in space. It has a certain “chance” to decay, not a determined life time. It is supposedly “structureless” so there’s no stuff “going on” inside to mark time, nor is there a specific environmental influence. But such particles just go “pop” at different times from their creation. This is “absurd” in classic QM manner. If environmental interaction was critical to when “collapse” happened, there should be some structure to muon decay depending on what is around it. After all, even if you say the superpositions of times of decay are part of overall statistics, the selection of “decay” versus “not yet” should be susceptible to being tweaked by environmental influences if “decoherence collapse” is valid.

More can be found at http://tyrannogenius.blogspot.com/2008/11/open-forum-dish-against-or-defend-many.html, anyone feel free to add more comments.

it is often said that decoherence is circular argument, but this is not correct. In the text the argument for decoherence is presented in enough detail to show the reader that there is no circular argument.

Decoherence has been measured and reproduced in simulations - to the disappointment of many - so it is the correct description of what happens. Prejudices have no role in physics, and even less in quantum theory.